Alberto Leon-Garcia

Autonomous Demand-Side Management Based on Game-Theoretic Energy Consumption Scheduling for the Future Smart Grid

Most of the existing demand-side management programs focus primarily on the interactions between a utility company and its customers/users. In this paper, we present an autonomous and distributed demand-side energy management system among users that takes advantage of a two-way digital communication infrastructure which is envisioned in the future smart grid. We use game theory and formulate an energy consumption scheduling game, where the players are the users and their strategies are the daily schedules of their household appliances and loads. It is assumed that the utility company can adopt adequate pricing tariffs that differentiate the energy usage in time and level. We show that for a common scenario, with a single utility company serving multiple customers, the global optimal performance in terms of minimizing the energy costs is achieved at the Nash equilibrium of the formulated energy consumption scheduling game. The proposed distributed demand-side energy management strategy requires each user to simply apply its best response strategy to the current total load and tariffs in the power distribution system. The users can maintain privacy and do not need to reveal the details on their energy consumption schedules to other users. We also show that users will have the incentives to participate in the energy consumption scheduling game and subscribing to such services. Simulation results confirm that the proposed approach can reduce the peak-to-average ratio of the total energy demand, the total energy costs, as well as each users individual daily electricity charges.

Information loss recovery for block-based image coding techniques-a fuzzy logic approach

A new technique to recover the information loss in a block-based image coding system is developed in this paper. The proposed scheme is based on fuzzy logic reasoning and can be divided into three main steps: (1) hierarchical compass interpolation/extrapolation (HCIE) in the spatial domain for initial recovery of lost blocks that mainly contain low-frequency information such as smooth background (2) coarse spectra interpretation by fuzzy logic reasoning for recovery of lost blocks that contain high-frequency information such as complex textures and fine features (3) sliding window iteration (SWI), which is performed in both spatial and spectral domains to efficiently integrate the results obtained in steps (1) and (2) such that the optimal result can be achieved in terms of surface continuity on block boundaries and a set of fuzzy inference rules. The proposed method, which is suitable for recovering both isolated and contiguous block losses, provides a new approach for error concealment of block-based image coding systems such as the JPEG coding standard and vector quantization-based coding algorithms. The principle of the proposed scheme can also be applied to block-based video compression schemes such as the H.261, MPEG, and HDTV standards. Simulation results are presented to illustrate the effectiveness of the proposed method.

Distributed Internet-Based Load Altering Attacks Against Smart Power Grids

With the increase in use of information technology in advanced demand side management and given the growth in power consumption in the computation and communications sectors, a new class of cyberintrusion plans is emerging that aims to alter the load through the Internet and by means of automatic and distributed software intruding agents. These attacks work by compromising direct load control command signals, demand side management price signals, or cloud computation load distribution algorithms to affect the load at the most crucial locations in the grid in order to cause circuit overflow or other malfunctions and damage the power system equipment. To gain insights into these less-examined yet important intrusion strategies, in this paper, we identify a variety of practical loads that can be volnurable to Internet-based load altering attacks. In addition, we overview a collection of defense mechanisms that can help in blocking these attacks or minimizing the damage caused by them. Our simulation results based on the standard setting in the IEEE 24-bus Reliability Test System show that our proposed cost-efficent load protection strategy can significantly reduce the cost of load protection while it guarantees that no Internet-based load altering attack may overload the power distribution system.

Coordination of Cloud Computing and Smart Power Grids

The emergence of cloud computing has established a trend towards building massive, energy-hungry, and geographically distributed data centers. Due to their enormous energy consumption, data centers are expected to have major impact on the electric grid by significantly increasing the load at locations where they are built. However, data centers and cloud computing also provide opportunities to help the grid with respect to robustness and load balancing. To gain insights into these opportunities, we formulate the service request routing problem in cloud computing jointly with the power flow analysis in smart grid and explain how these problems can be related. Simulation results based on the standard setting in the IEEE 24-bus Reliability Test System show that a grid-aware service request routing design in cloud computing can significantly help in load balancing in the electric grid and making the grid more reliable and more robust with respect to link breakage and load demand variations.

Game-Theoretic Demand-Side Management With Storage Devices for the Future Smart Grid

We study the demand side management (DSM) problem when customers are equipped with energy storage devices. Two games are discussed: the first is a non-cooperative one played between the residential energy consumers, while the second is a Stackelberg game played between the utility provider and the energy consumers. We introduce a new cost function applicable to the case of users selling back stored energy. The non-cooperative energy consumption game is played between users who schedule their energy use to minimize energy cost. The game is shown to have a unique Nash equilibrium, that is also the global system optimal point. In the Stackelberg game, the utility provider sets the prices to maximize its profit knowing that users will respond by minimizing their cost. We provide existence and uniqueness results for the Stackelberg equilibrium. The Stackelberg game is shown to be the general case of the minimum Peak-to-Average power ratio (PAR) problem. Two algorithms, centralized and distributed, are presented to solve the Stackelberg game. We present results that elucidate the interplay between storage capacity, energy requirements, number of users and system performance measured in total cost and peak-to-average power ratio (PAR).

Performance of buffered banyan networks under nonuniform traffic patterns

An analytical method of evaluating the performance of the buffered banyan packet-switching network under nonuniform traffic patterns is presented. It is shown that nonuniform traffic can have a detrimental effect on the performance of the network. The analytical model is extended to evaluate the performance of multibuffer and parallel banyan networks. These modified networks are shown to have better throughput capacity and delay performance than the single-buffer banyan network. >

A source matching approach to finding minimax codes

A source matching approach is presented to the problem of finding minimax cedes for classes of memoryless sources. The approach leads to a channel capacity problem so that Blahuts algorithm can be used to find approximations to the minimax code. Closed form solutions are presented for the class of monotonic sources and for a class of Bernoulli-like sources. For extensions of finite alphabet memoryless sources, a modified Lynch-Davisson code has performance close to that of the minimax code. The exact solution to the source matching problem and the resulting codes are presented for the extensions of binary codes up to blocklength 31.

A self-routing multistage switching network for broadband ISDN

A switching network that approaches a maximum throughput of 100% as buffering is increased is proposed. This self-routing switching network consists of simple 2*2 switching elements, distributors, and buffers located between stages and in the output ports. The proposed switching requires a speedup factor of two. The structure and the operation of the switching network are described, and its performance is analyzed. The switch has log/sub 2/N stages that move packets in a store-and-forward fashion, incurring a latency of log/sub 2/N time periods. The performance analysis of the switch under uniform traffic pattern shows that the additional delay is small, and a maximum throughput of 100% is achieved as buffering is increased. >

Performance Analysis of Integrated Voice and Data Hybrid-Switched Links

Numerical techniques for the solution of a class of twodimensional Markov processes are presented. These techniques are used to analyze the performance of several versions of hybrid switching including the movable boundary scheme with finite or infinite buffers, with flow control, and with or without TASI. Also included are results for TASI in which the number of off-hook calls is not fixed. Finally, the accuracy of the quasi-static approximation is evaluated for several problems.

Performance Evaluation Methods for an Integrated Voice/Data Link

This paper presents an approximation method for estimating the average number of data packets in a SENET-concept integrated voice and data system. The method is simple to use and its estimates are found to be in good agreement with simulation results. In general, the method applies to any system that integrates packet traffic with a more slowly varying traffic class that can preempt a portion of the packet transmission capacity.